Socially Acceptable

Everyone's been raised to be "social." You remember: elbows off the table, speak only when spoken to, only pierce your ears, etc. I really wanna know, who judges on what's "acceptable" and what isn't? I mean, since when did the "emo's" become outcasts? Really, is wearing $200 jeans logical? I don't grasp how some trends make it while others fail.
For instance, who decided that wearing clothes was mandatory in public? Sure, they have nudist colonies, but still. Is it because some people are obese and no one wants to see what they have, or is it because then all the men would have contests? Another thing is hair. Seriously, why does green hair freak people out? It's on their scalp, they could do with it as they please.
What happened to the saying "To each their own?" How did it become "Their own to each and every?"
I guess this was more of a rant. But still, since when is having your ears pierced three times instead of one unacceptable?